Powerturn belts are a type of specialized conveyor belts wherein the conveyor belt does not travel in a straight path parallel to its longitudinal length. At a minimum, powerturn belts travel through a 30° arc. At the extreme end, a powerturn belt will travel multiple 360° turns in what is referred to as a spiral conveyor. Such belts have applications in a variety of industries, varying from warehouses, airports, and the food industry.
To assist the belt in turning, at least one longitudinal edge of the belt is provided with means that are mechanically gripped by the conveyor system. Such means includes guide means as shown in U.S. Pat. No. 3,951,256 and resin moldings, such as disclosed in U.S. Pat. No. 6,834,760.
Conventional conveyor belts for powerturn applications are formed of several thin plies of a simple warp/weft woven fabric, wherein both plies have the same reinforcement structure. The reinforcement structure is embedded in either an elastomeric or plastic matrix such as PVC, depending on the powerturn system requirements. While such belts have proven satisfactory in the past, such belts fail to consider the different tensions placed on the belt due to the curves and u-turns the belt travels in the powerturn system. This can lead to an reduction in durability and performance of the conveyor belt.